


Iron

by Kestrealbird



Category: Fate/stay night & Related Fandoms
Genre: Fionn and Dia are both badass, Light Angst, Other, i want saber fionn so i delivered, man just read it, maybe idk, more like mild violence than graphic i think?, tags are hard for this one
Language: English
Status: Completed
Published: 2020-04-16
Updated: 2020-04-16
Packaged: 2021-03-02 00:33:39
Rating: Teen And Up Audiences
Warnings: Graphic Depictions Of Violence
Chapters: 1
Words: 2,105
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23686216
Author URL: https://archiveofourown.org/users/Kestrealbird/pseuds/Kestrealbird
Summary: His assailant sneers down at him; Diarmuid, despite the pain he’s in, forces himself to smirk back, unsurprised when the act is met with a sharp stamp to his shoulders.“Wow,” he wheezes, “normally you’re meant to buy me dinner before hitting third base aren’t you?” No response, outside of the grip on his hair tightening. “No manners huh? Typical.”
Comments: 2
Kudos: 30





	Iron

**Author's Note:**

> You know when you're just struck with an idea and you have to get it out? Yeah. Anyway enjoy whatever this is lmao!

Iron wasn’t something that Diarmuid had ever thought he’d have to deal with as a Servant. Not to this degree - pinned to the ground by a thick rod of it impaled through his back and stomach, an iron boot pressing even harder between his shoulder-blades, the floor beneath him and the walls around him the same cold, painful metal.

It was meant to be a simple mission. Gather the materials that were needed to fix Chaldea’s inner workings and come back within the day. Nobody had expected a trap to be laid for them here; he wondered -  _ hoped  _ \- if Merlin and Ibaraki were in better condition. These people were Magus’ specifically trained to hunt the paranormal, the inhuman.

Diarmuid had been separated from the other two when the ground beneath them had given way, and he’d fallen down into this caged area of iron, unable to re-orient himself in time to dodge the rod that currently brushed right below his lungs. Merlin and Ibaraki, last he’d seen them, had been further away from the ensuing collapse, given more time to escape, and with Merlin’s proclivity for illusions and Ibaraki’s natural born stubbornness, Diarmuid normally wouldn’t doubt their safety, but faced with a group like this...he cannot help his worry.

Surprisingly, he’d managed to quell the agonized scream that had worked its way into his throat, but there was little he could do to hide his thick, bloodied tears staining earthly cheeks. His glamour, normally worn around him like a second,  _ tight  _ skin, had been forcibly torn apart from his person, and the black glass shards of it lay glittering in a mocking pool around him.

Gritting his teeth as tight as he dares, Diarmuid reaches out for his spears, but both of them lay far away from him, and he curses himself for dropping them at that first  _ vicious  _ torrent of pain as he’d fell between the iron bars and beams beneath the concrete.

A hand fists itself into his hair, snapping his head back so quickly that it forces a whimper from his throat. Diarmuid glares up at his assailant, defiant and angry. He won’t die here, he knows that, but when faced between death and the possibility of losing  _ himself  _ -

He knows which one he’ll choose. Diarmuid’s name is his own. He  _ will not  _ give them the satisfaction of taking it from him.

The face above him seems familiar, but there are so many people in Chaldea that it’s hard for him to place any specific name to the person, and his mind is fuzzy at the edges, dulled by the iron around him. Every breath he takes  _ burns  _ his lungs something fierce, and more tears fall as a result, dripping to the ground beneath him. They sizzle on impact, turning into normal wisps of smoke as the iron burns away at them.

His assailant sneers down at him; Diarmuid, despite the pain he’s in, forces himself to smirk back, unsurprised when the act is met with a sharp stamp to his shoulders.

“Wow,” he wheezes, “normally you’re meant to buy me dinner before hitting third base aren’t you?” No response, outside of the grip on his hair tightening. “No manners huh? Typical.”

Talking is definitely a bad idea, all things considered, but it’s also the only way he can think to keep himself awake enough to fight off the bright, thieving sigils that have begun to hum and align themselves around him. “You know,” Diarmuid continues, “I think that using -” another wave of pain, this time near his ribs - “this much force is more detrimental to you than helpful. I mean, what are you going to do if I pass out?” A grin, or as much of one as he can manage. “Can’t exactly take someone's name if they’re not awake enough to give it to you.” The assailant stiffens, grey eyes narrowing down at him. Ah, so they thought he wouldn’t catch on. Either these people have forgotten who he is, or they’ve  _ severely  _ underestimated his intelligence.

Diarmuid chooses to believe it’s the former, because the latter would just be downright  _ insulting.  _ He hasn’t beaten Fionn at chess for their entire lives just to be compared to  _ Billy  _ of all people. 

“Your plan wasn’t exactly subtle. The iron was a dead giveaway really.” 

That’s not even an exaggeration. Any fae worth their weight would be able to pick up on such an obvious ploy, let alone a fae of  _ his  _ particular ilk. “So what’s your big plan, hm? You take my name and then use me as a mana battery? Turn me against my allies in the hopes that any of them will be dumb enough to hesitate kicking my ass?” 

The first one might be a problem, but he doubted the second would work. He could already name around twenty people off the top of his head that would be more than happy to take an excuse to beat him into the dirt, and  _ half  _ of those people even called themselves his friends.

There was a third thought, however, that left him the most uneasy. If they took his name, if they had a  _ proper  _ plan, then they could give themselves access to his homeland, and there would be no telling what the mages would cause by doing such a dangerous thing. The balance between the fae and the humans was a thin one. If anything were to upset that then…

He shivers, the image of his fathers donning themselves for war setting his teeth on edge. Chaldea has fought Gods before, true, but it has always been a close thing, and always -  _ always  _ \- on human soil. His people would never give them that privilege. There is, afterall, more than one way to win a war.

Before anything, Diarmuid needs to find out what these traitors are planning, if anything at all, and to do that...well. He’s always been rather good at bluffing.

“Those sigils won’t work on me. It’s a good plan, don’t get me wrong, but I’m a little more than just your basic backwater fairy.” He closes his eyes as he talks, forcing himself to relax. The less distressed he makes himself seem, the more likely this person is to believe him. It’s why they’re still letting him talk.

Amateur.

“You could try and torture it out of me.” His comment, light and seemingly unconcerned, causes the smallest of twitches from his assailant. The iron burns his tongue. Diarmuid keeps talking. “I’m sure you’d have some fun stories to tell afterwards. It’d be a nice conversation opener wouldn’t it? ‘Hey guess what I did recently? Tortured a fae so badly he gave up his name just to stop it.’” 

“...”

My, my, was that hesitation he could feel? Were they not prepared for such a drastic measure? Nothing more than a child acting tough. No matter. Diarmuid wouldn’t take it easy on them just for something like that. 

He lowers his voice to an almost sinful degree. With his glamour shattered, there would be nothing to protect this person from his suggestions. Good. Makes the whole thing easier, not that he likes to do it. “If you asked me nicely,” he purrs, “I could give it to you freely. You wouldn’t have to hurt me then. I’m not a huge fan of pain, you see -” a half-lie - “and I’d prefer it if you didn’t rip my name out of my insides.”

A sharp intake of breath. “We don’t...tear it out…”

They’re right, but it’s a close thing, and now they sound uncertain. 

“Ah,” he says cheerfully, “so you can speak!”

His head slams into the ground. Diarmuid half-expected it, so he quells the cry of pain into a simple grunt instead. He burns.

“You’re offering a deal,” they hiss, “and deals with your kind never end well.”

Diarmuid’s laughter is more breathless than it should be. His mind fogs further.  _ Not yet, _ he tells himself,  _ don’t pass out yet. _

“And how would you know? Ever tried it before?”

A heated, angry glare. Hm. Maybe they have then. That certainly complicates things. “Say you  _ did  _ give it to me,” they snarl, “what would you want in return? My first born? My soul?”

Diarmuid rolls his eyes. “Don’t be so cliche about it. I just want to know what you’re going to use it for, that’s all.”

A beat of silence, broken swiftly by harsh, maniacal laughter. The amount of people who think that laugh is  _ unique, _ let alone _ frightening, _ is truly tremendous. He’s gotten bored of it already.

“That’s all you want to know? Doesn’t seem like a fair deal to me.”

Diarmuid shrugs. “Curiosity killed the cat, yeah? Humour me.”

The assailant shakes their hand, and the look of amusement they give him makes Diarmuid want to tear their throat out with his jaws. “Mana battery? Use you against your friends? Well, you’re partly right.”

“...”

They smile. It looks ugly and disjointed and slimy. Diarmuid hates it. “What we really want is a catalyst, one that can only really work  _ here, _ in Ireland.”

A catalyst that works in Ireland? So they want to create a pseudo-servant. But, if that’s the case, why would they need him specifically and not…

Oh.

_ Fuck. _

“No.” Diarmuid’s voice tightens on the word, pain receding into something duller as their plan for him takes form in his mind. “You...you know my father.”

Another smile, slimier than the last. “We do.”

Of  _ course  _ that’s what they want! The mages are obsessed with getting to The Root, and in their minds the best way to do so is through sacrifice and bloodshed. What better way to have those requirements met than to use a God of The Dead. 

They need  _ him  _ because Donn is his _ father, _ and pseudo-servants are better when used with blood relation. But they don’t know his father like he does. They don’t know what Donn is  _ capable  _ of, nor what he’ll  _ do  _ to them the moment he appears.

“You won’t get the root that way -”

“Liar.” 

Great. They’re a fanatic too.

Rattled more than he’d like to admit to anyone, least of all himself, Diarmuid takes stock of the sigils around him. If he can just find where the originate…

_ There. _

What he does next can only be described as stupid and suicidal. He would’ve done it regardless of the answer, but he’s in a hurry this time. Merlin and Ibaraki will be safe, he’s surer of that now than he was before, but they’ll also be too distracted by whatever the mages sent after them to help him.

Taking the deepest breath he can manage, Diarmuid plants his hands on the iron ground, forcing himself onto his knees. The rod in his back knicks one of his lungs, because of course it does. Diarmuid ignores it. Instead, he grabs the rod with both hands and, holding it in place -

Wrenches himself away from it, tearing up his entire left side in the process, and makes a frantic dive for his spears while the mage looks at him in a horrified stupor.

Gae Dearg is slippery in his grip, the blood on his hands making it difficult to get a proper handle on it, but Diarmud manages, somehow, and dodges the incoming blast of magic propelled his way. 

Staggering to his feet, Diarmuid sends a prayer to the skies, and summons the one item that he couldn’t in any other area.

What he does is stupid, foolish and overall idiotic. But there is more than one God in Ireland, and Diarmuid was going to visit his friend later anyway. It won’t be an ideal reunion, but he’s sure his friend will forgive him for it later.

With both hands held firmly on his spear, Diarmuid stabs Gae Dearg into the ground, destroying the sigils and barriers in a single, well-aimed strike, and as the mage screeches at him with fury - as Diarmuid himself, exhausted, falls to his knees, grip on his spear never loosening - he manages a smile.

“Hey...remind me again  _ exactly  _ whose mountain you think we’re on.”

The force of the magic dispersing around them sounds off the horn propped on the floor next to him, loud enough that he’s certain it can be heard for miles.

The mage readies another spell. They never get to cast it.

“Tell me,” a voice so deep and familiar it makes Diarmuid shudder rings out around them, and he’s never been happier to see Fionn’s sword, bright blue and wider than his body, severing someone's head from their neck. “How  _ do  _ you get yourself into these situations, Diarmuid?”   
  


**Author's Note:**

> Some little mythos notes here! "A fae of his particular ilk" is me referencing the fact that Diarmuid's father, Donn, is a member of the Tuatha De Dannan, the irish pantheon, but is also a first generation Fae Folk! In other words, he was one of the first Fae to ever sit foot in Ireland at all! So yeah Dia is part fae himself, along with being a demi-god, and that's also why the whole iron weakness thing happens
> 
> "Bloodied tears" this is a deep cut but the TLDR is that Donn may have been an aspect of the King of the Irish Gods, Dagda, who was noted for crying tears of blood.
> 
> "Fathers" - he's talking about his foster fathers here, Aengus and Manannan, the god of Love and the Ocean respectively, who are also Kings of their own realm within the overall "otherworld/Fae realm"
> 
> Donn had no problem, in myth, crushing the head of a human child just because he was jealous the kid was getting more attention than he was. So yeah. Good luck with that mages.
> 
> Finally, the mountain they're on is the Hill of Allen, the place where Fionn lived and also where he's either buried or sleeping under until someone sounds his horn, the Dord Fiann, to wake him up. This is the horn Diarmuid summons naturally.


End file.
